I use S&W .38 nickel plated brass with my .357/.38 dies...I load .358" lead over 2 grains of Red Dot...Mild and accurate in my Albion Motors made Enfield...

There has been such a variance in the bores of ".38 S&W" over the years, the ammo makers of today use a small diameter hollow base bullet that 'slugs up' to the bore upon firing...At least the Winchester and Remington factory slugs I have pulled fit this description...

I have an old Ideal manual that calls for bullets from .354"-.360" depending on your individual bore...